Urban truck traffic has boomed alongside the rise in e-commerce. As shown in a recent Brookings Institution blog post, while both urban truck and passenger VMT have been growing faster than urban populations since the 1960s, urban truck traffic diverged from urban car travel in the early 1990s and exploded between 2006 and 2008 before a slight dip during the recession. Thanks to this growth, total single unit (box) truck VMT became majority urban in the early 2000s, and combination (tractor-trailer) truck VMT is likely to become majority urban in the coming years.

If the rapid growth in urban truck VMT is a result of increasing e-commerce deliveries, we are a long way from peak urban truck traffic. Today, e-commerce represents only 7% of total retail sales yet accounted for about half of the growth in total retail sales during the first quarter of this year.

Continued growth in e-commerce will challenge cities to implement new policies to reduce the negative impacts of increasing truck traffic by adjusting parking policies, promoting off-peak delivery, clustering freight facilities, and segregating truck traffic from bicyclists, pedestrians, and other vehicles where possible. Policies such as these are detailed in a 2013 SSTI report.

Despite the negative impacts associated with increasing truck traffic, buying online generally appears to be more environmentally friendly than driving to brick-and-mortar stores to make your purchases. In a 2011 blog post, the LA Times cited a study from Carnegie Mellon, which estimated that e-commerce requires about 30% less energy than traditional retail. This disparity is primarily due to e-commerce trucks making many deliveries on each trip—using far less fuel for each delivery than a typical consumer would use driving to the store and back.